The de Rham complex on unbounded domains with Sobolev space topology

This paper studies the operator dd^∗+d^∗d acting on q-forms on an unbounded domain with smooth boundary, where d is the exterior derivative and d^∗ is the adjoint of d calculated using the Sobolev space topology. The domain of d^∗ is determined and an expression for d^∗ is obtained. The operator dd^∗+d^∗d gives rise to a boundary value problem. Global regularity is obtained using weighted norms and global existence is obtained by using the theory of compact operators.     

关于下半连续函数的性质

证明了局部紧且具有可数基的度量空间上的弱下半连续函数和自反的巴拿赫空间上的弱下半连续函数的间断点集合都是第一纲集。     

几乎概率赋范空间中的拓扑度理论与不动点定理

首先研究了几乎概率赋范空间的拓扑结构,接着在包含全连续场在内的一类映象上建立了拓扑度,最后利用这种拓扑度理论得到了一些新的不动点定理.     

拟极小集及其对于连续偏序集理论的应用

本文以拟极小集概念为基础,论述了连续偏序集的刻划问题,对于连续偏序集之间的余态射作了详细的分析。对J.D.Lawson和R.E.Hoffmann所确立的完全分配格与连续偏序集间的对应关系给出了一种新的处理。     

Filters,Antichains and Towers in Topological Spaces and the Axiom of Choice

We find some characterizations of the Axiom of Choice (AC) in terms of certain families of open sets in T₁ spaces.     

Some topologies on a Šerstnev probabilistic normed space

In this paper we will introduce two other topologies, coarser than the so-called strong topology, on a class of Šerstnev probabilistic normed spaces, and obtain some important properties of these topologies. We will show that under the first topology, denoted by τ₀, our probabilistic normed space is decomposable into the topological direct sum of a normable subspace and the subspace of probably null elements. Under the second topology, which is in fact the inductive limit topology of a family of locally convex topologies, the dual space becomes a locally convex topological vector space.     

关于Erceg伪度量与点式伪度量的一点注记

文[13]曾证明Erceg伪度量与史福贵提出的点式伪度量等价.本文指出[13]中的定理1是错误的,进而指出Erceg伪度量与点式伪度量是不等价的.     

Erratum to ``Baire spaces and Vietoris hyperspaces'

The main purpose of this short note is to correct an error in ``Baire spaces and Vietoris hyperspaces', Proc. Amer. Math. Soc. 135 (2007), no. 1, 299-303.

     

The Theory of Multidimensional Persistence

Persistent homology captures the topology of a filtration—a one-parameter family of increasing spaces—in terms of a complete discrete invariant. This invariant is a multiset of intervals that denote the lifetimes of the topological entities within the filtration. In many applications of topology, we need to study a multifiltration: a family of spaces parameterized along multiple geometric dimensions. In this paper, we show that no similar complete discrete invariant exists for multidimensional persistence. Instead, we propose the rank invariant, a discrete invariant for the robust estimation of Betti numbers in a multifiltration, and prove its completeness in one dimension. The first author was partially supported by NSF under grant DMS-0354543. The second author was partially supported by DARPA under grant HR 0011-06-1-0038 and by ONR under grant N 00014-08-1-0908. Both authors were partially supported by DARPA under grant HR 0011-05-1-0007.